Assuming that Open the Vaults IS in M11 (doubtful given the scars of mirrodin ott synegy), I am consider beginning to think about something like this for nats (not PTQs, China etc.)

It's an open the vaults deck (i.e. deck that will never lose to any form of wu control EVER). Vs aggro strategies the plan is to transform into a planeswalker wu type control deck when they sideboard out removal. I think open has a good matchup vs most decks in the format g1 (wu and wur v. good, jund and bant good, naya bad, mono red v. bad) post sb you can change your plan of attack by sideboarding out howling mine, up to 3 kaleidostone, up to 2 time warp, and 1 time sieve (jace beleren possibly on the draw). Angelsong allows you to keep in the mines g3 if you wish vs naya.

This sort of deck has been covered in depth already last season, so I am sure you all know how to play it. I will however say that everflowing challice is an ABSOLUTE BOMB in this sort of a deck, costing 1 mana (you never cast it turn 2 unless you are intending to follow with a borderpost). On turn 4 it allows you to play it and a draw artifact on the same turn. Prophetic prism is possibly one of the very best cards this deck could hope to get too, it fixes your mana, negates spreading seas, turns challice mana into relevant mana and is a good sac outlet to time sieve. My argument is that this deck was very playable last summer, but has gained a lot from recent sets, and is now well positioned to be played in t2 (especially given that wall of omens and gideon has made the decks that it beats even better). Testing so far seems to back this up.

But why am I posting this here? I want you to rip this deck to pieces, tell me why it's a terrible choice and question anything and everything about the deck. This should give me ideas for improvement. Thanks for you time